Your Digest for Thursday, Jan 11, 2024 09:59 PM


PDB is an ancient disease, claimed to be identified in a Neanderthal skull;

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Blackwater fever is a rare complication of malaria which can be fatal. It is caused by large intravascular haemolysis resulting in haemoglobinuria, anaemia, jaundice and acute kidney injury. Urine is classically black or dark red in colour.The cause of the massive haemolysis is unknown. The treatment is with antimalarials, intravenous fluids and in some cases dialysis. Urinalysis reveals blood which is not seen on microscopy as it is haemoglobinuria.
[!INFO] AKA Bilharziasis
after the name of the disoverer
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[!TIP] Mnemonic for the species:


[!INFO] In general
G protein coupled: regulate slow processes

Eg: Muscarinic

Ligand gated ion channels : fast processes (like neurotranmission)

Eg: GABA, Glutamate, Nicotinic

Mnemonic: MG (myasthenia gravis ) Muscarinic -> G protein, Nicotinic -> ligand gated.

Enzyme linked receptors

Receptor tyrosine kinases are the commonest type of enzyme linked receptors.
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Enzyme linked receptors are receptors which

 3 Main Types of Enzyme-Linked Receptors

  1. Receptor Tyrosine Kinases [RTK] • make up the majority of enzyme-linked receptors.

  2. Serine/Threonine Kinases

  3. Tyrosine Kinase-Associated Receptors [“mixed”] • do not have a tyrosine kinase domain, rather act through cytoplasmic tyrosine kinases.

Mechanism of transduction

  1. Ligand binding leads to dimerization of two neighboring receptors.
  2. Neighboring dimerized receptors auto phosphorylate one another
  3. SH2-domain proteins bind to the phosphorylated receptors and are then phosphorylated enabling the continuation of the signal eventually leading to gene transcription.

Tyrosine kinases


Spondyloarthritis (SpA)

Inflammatory osteoproliferative lesions in the spine are called syndesmophytes (marginal and non-marginal), and degenerative osteoproliferative lesions are called osteophytes. Syndesmophytes are more vertically oriented than osteophytes.

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Syndesmophyte Osteophyte
Arise from calcification withn ligaments Arise from bone (vertebral bodies)
Seen in inflammatory (spondylo) arthropathies See in Osteoarthritis
Source

[!TIP] Mnemonic: RePsAnkIb

Ankylosing = stiffness or fixation of a joint by disease
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- Advanced cases: fusion of the sacroiliac joints, and bamboo spine. (Gadolinum MRI is more sensitive than Xray at detecting early changes).

Diagnosis

"Plain x-ray of the sacroiliac joints is the most useful investigation in establishing the diagnosis."

The sacroiliac joint is actually a synovial joint with hyaline on the sacral surface and fibrous cartilage on the iliac surface Source.

Bone changes seen in various diseases

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Langerhans cell histiocytosis